JP6690877B2 - Carbonization equipment for woody biomass - Google Patents

Description

  The present invention relates to a carbonization apparatus for woody biomass that performs carbonization by indirectly heating woody biomass in a reducing atmosphere.

  In recent years, for the purpose of preventing global warming, effectively using resources, etc., wood-based biomass such as waste wood and thinned wood, which were conventionally cut out as unused wood from the forest and discarded, is processed into chips, Attention has been paid to a biomass power generation system in which this is combusted as a biomass fuel in a boiler, and the steam turbine is rotated by the high-pressure steam generated thereby to generate electric power. On the other hand, even with the same wood-based biomass, for example, pruning branches and rooting materials that are also called difficult-to-use materials, bark, and scrap materials that are generated at construction sites, etc. Alternatively, construction waste materials generated at the site of dismantling a building, etc. are not uniform in size and properties, the heat generation amount also varies, and impurities are easily mixed in. It is not suitable, and most of them are still disposed of as industrial waste for a fee.

  If wood-based biomass such as such difficult-to-use materials is not burned as it is, but is carbonized using, for example, a carbonization furnace, it can be adjusted to a constant calorific value and can be burned stably. It is thought that it can be recovered as charcoal fuel that can be used as fuel for burners by further pulverizing it, but too much cost (for example, fuel cost for heavy oil used in carbonization furnaces) It is not realistic to carry out the carbonization treatment by multiplying by. On the other hand, regarding such a problem, for example, Patent Document 1 (JP 2012-224677 A) discloses that biomass has a particularly high water content and is difficult to burn as it is, for example, food processing residues, food waste, livestock excrement, Wet-type biomass such as sewage sludge is treated, first, the wet-type biomass is dried by aerobic fermentation, and then supplied to an indirect heating type carbonization furnace to be carbonized and recovered as carbonized matter, while the carbonization is performed. In addition to burning and decomposing the tar component, which is a volatile component generated with the carbonization process in the furnace, in the combustion furnace, the hot air generated at that time is effectively used as an indirect heating source of the carbonization furnace, and as much as possible of heavy oil, etc. A carbonization system for wet biomass is described which is adapted for carbonization without the use of fossil fuels.

JP 2012-224677 A

  However, in the above-mentioned conventional apparatus, since the object to be carbonized is wet type biomass such as food waste or sewage sludge, carbonization is carried out in a high water content state, and it is relatively conventional. The amount of tar generated by carbonization in a high temperature range is small, and even if all of it is combusted and decomposed to generate hot air, it is insufficient in calorific value to be used as an indirect heating source for the carbonization furnace. It is designed to generate as much tar component as possible by performing a drying treatment by aerobic fermentation in advance and a carbonizing treatment in a relatively low temperature range. On the other hand, when the object to be carbonized is a wood-based biomass as described above, since the tar content in the biomass is originally large, a relatively large amount of tar component is likely to occur regardless of the temperature range for carbonization. Although the above problems such as insufficient heat are unlikely to occur, if the tar components that are generated in large quantities are combusted and decomposed in the combustion furnace, in some cases there will be too much heat, and if it is supplied to the carbonization furnace as an indirect heating source, it will be treated. The carbonization temperature of a certain wood-based biomass becomes too high, and as a result, only the charcoal that is completely vaporized of the tar component and hardly remains is recovered.For example, as a charcoal fuel for a burner that requires relatively high ignitability. There is a concern that the uses of the recovered carbide will be limited, such as not being very suitable. The hot air temperature can be adjusted to a temperature suitable for carbonizing a desired carbide by introducing, for example, outside air into the hot air supplied from the combustion furnace to the carbonization furnace and forcibly cooling it. However, it is simply wasted in terms of thermal energy.

  In view of the above points, the present invention, by combusting and decomposing a tar component generated with the carbonization treatment of woody biomass in a hot air generating furnace, while effectively utilizing the hot air generated at that time as an indirect heating source of the carbonizing furnace, Carbonization treatment of woody biomass that can control the hot air temperature suitable for carbonizing the charcoal of desired properties by separating and recovering the excess heat amount from the tar component supplied to the hot air generator An object is to provide a device.

In the carbonization treatment apparatus for woody biomass according to claim 1 of the present invention, a carbonization furnace for indirectly heating and carbonizing woody biomass in a reducing atmosphere, and a carbonization treatment for woody biomass in the carbonization furnace A hot air generating furnace that generates hot air by burning and decomposing the wood gas generated by self-combustion is provided side by side, and the hot air generated in the hot air generating furnace is supplied to the carbonization furnace as a heat source for indirect heating. A carbonization device for woody biomass, which is contained in wood gas by heat exchange between wood gas derived from the carbonization furnace and outside air supplied from an outside air supply fan between the carbonization furnace and the hot air generating furnace. Along with an air-cooled heat exchanger capable of condensing and recovering a part of the high boiling point tar component, a carbide temperature sensor for detecting the temperature of the carbide in the furnace is provided in the carbonization furnace, or a downstream of the hot air generating furnace. Fever Comprising a hot air temperature sensor for detecting the temperature of hot air derived from the generation furnace, carbides temperature or the temperature of hot air hot air generator furnace downstream detected by the sensor the hot air temperature inside the carbonizing furnace detected by the carbide temperature sensor Is provided with a tar combustion amount controller for adjusting and controlling the amount of outside air supplied from the outside air supply fan so as to maintain a predetermined temperature.

  The woody biomass carbonization apparatus according to claim 2 further comprises a combustion air supply duct for guiding the outside air supplied from the outside air supply fan to the air-cooled heat exchanger into the hot air generating furnace. There is.

  In addition, in the carbonization treatment device for woody biomass according to claim 3, an outside air inlet is freely opened and closed on the downstream side of the air-cooling heat exchanger of the combustion air supply duct, and hot air downstream of the hot-air generation furnace is provided. If the residual oxygen concentration in the inside is lower than a preset lower limit residual oxygen concentration, the outside air introduction port is opened to introduce the outside air into the hot air generating furnace.

  Further, in the carbonization treatment apparatus for woody biomass according to claim 4, a drying furnace for drying the woody biomass before carbonization in the middle of an exhaust duct for exhausting hot air supplied to the carbonization furnace as a heat source for indirect heating. Alternatively, it is characterized by interposing a sand dryer for drying the sand, which is the material of the asphalt mixture.

According to the carbonization treatment apparatus for woody biomass according to claim 1 of the present invention, a carbonization furnace for indirectly heating and carbonizing woody biomass in a reducing atmosphere, and a carbonization treatment for woody biomass in the carbonization furnace. Along with a hot air generating furnace that combusts and decomposes the wood gas generated by the above by self-combustion to generate hot air, and supplies the hot air generated in the hot air generating furnace to the carbonization furnace as a heat source for indirect heating. In the carbonization treatment apparatus for woody biomass, the wood gas derived from the carbonization furnace and the outside air supplied from the outside air supply fan are heat-exchanged between the carbonization furnace and the hot air generating furnace to generate heat in the wood gas. Is provided with an air-cooled heat exchanger capable of condensing and recovering a part of the high-boiling tar component contained in the carbonization furnace, and a carbide temperature sensor for detecting the temperature of the carbide in the furnace, or the hot air generating furnace. Downstream of Comprising a hot air temperature sensor for detecting the temperature of hot air derived from the hot air generator furnace, carbides temperature or the hot air generator furnace downstream of hot air detected by the hot air temperature sensor in said carbonizing furnace detected by the carbide temperature sensor Since a tar combustion amount controller for adjusting and controlling the amount of outside air supplied from the outside air supply fan to adjust the amount of tar combustion in the hot air generating furnace so that the temperature is maintained at a predetermined temperature is provided , woody biomass While effectively utilizing the hot air generated by the thermal decomposition of the tar component generated by the carbonization process in the hot air generation furnace as an indirect heating source of the carbonization furnace, the surplus from the tar component supplied to the hot air generation furnace. The amount of heat can be separated and recovered to adjust the amount of tar combustion, and the hot air temperature can be controlled to a value suitable for carbonizing the carbide of the desired properties from the woody biomass. , It is possible for example such recovering carbides suitable for charcoal fuel or the like for good burner to the ignitability to moderately leaving tar components.

  Further, according to the woody biomass carbonization apparatus of claim 2, since the combustion air supply duct for guiding the outside air supplied from the outside air supply fan to the air-cooled heat exchanger into the hot air generating furnace is provided, The outside air heated by heat exchange with wood gas can be effectively used as it is as combustion air for temperature adjustment and self-combustion of the hot-air generating furnace, effectively increasing combustion efficiency in the hot-air generating furnace. You can

  Further, according to the woody biomass carbonization apparatus of claim 3, an outside air inlet is openably provided on a downstream side of the air-cooling heat exchanger of the combustion air supply duct, and the outside of the hot air generating furnace is downstream. If the residual oxygen concentration in the hot air is lower than the preset lower limit residual oxygen concentration, the outside air inlet is opened so that the outside air is introduced into the hot air generating furnace. When the outside air is not supplied from the outside air supply fan to the air-cooled heat exchanger, or when the outside air supplied to the air-cooled heat exchanger is heated by heat exchange and causes thermal expansion to decrease the oxygen concentration. However, the amount of oxygen required for self-combustion can be stably supplied to the hot air generating furnace, and problems such as incomplete combustion and misfire can be prevented.

  Further, according to the carbonization apparatus for woody biomass according to claim 4, a drying furnace for drying woody biomass before carbonization in the middle of an exhaust duct for exhausting hot air supplied to the carbonization furnace as an indirect heating source. Alternatively, since a sand dryer for drying the sand, which is the material of the asphalt mixture, is interposed, the amount of heat possessed by the hot air generated by the combustion decomposition of the tar component in the hot air generating furnace can be effectively used without waste. Further, the temperature of the hot air generated in the hot air generating furnace is maintained at a substantially constant temperature by adjusting the amount of tar combustion by the air-cooled heat exchanger, so that the wood-based biomass or sand that is the material to be dried is It is convenient because it can be uniformly dried without variation.

It is a schematic explanatory drawing which shows one Example of the carbonization processing apparatus of the woody biomass which concerns on this invention. It is a flow chart which shows the control processing procedure at the time of adjusting and controlling the amount of tar combustion in the hot-air generation furnace of the said carbonization processing apparatus. Explanation of woody biomass and sand with high water content processed by the carbonization apparatus for woody biomass according to the present invention to collect as carbonized material, tar and dry sand, and to make effective use in an asphalt mixture manufacturing plant It is a figure.

  In the woody biomass carbonization apparatus according to the present invention, there is provided a carbonization furnace that indirectly heats woody biomass in a reducing atmosphere to perform carbonization, and a flammable wood produced by the carbonization in the carbonization furnace. A hot-air generating furnace that combusts and decomposes gas by self-combustion to generate hot air is provided side by side, and the high-temperature hot air generated in the hot-air generating furnace is supplied to the carbonization furnace as a heat source for indirect heating. Along with the carbonization furnace and the hot air generating furnace, heat exchange is carried out between the wood gas derived from the carbonization furnace and the outside air supplied from the outside air supply fan, and the high boiling point tar component contained in the wood gas. It is equipped with an air-cooled heat exchanger that condenses and recovers a part of it.

  Further, the outside air supply fan is configured to adjust and control the amount of outside air to be supplied so that the temperature of the carbide in the carbonization furnace or the temperature of the hot air downstream of the hot air generation furnace is maintained at a predetermined temperature. Then, for example, if the carbide temperature or the hot air temperature is higher than the treatment temperature range suitable for carbonizing the carbide having the desired properties, a considerable amount of outside air is supplied, and the wood gas temperature is lowered to remove the tar component having a high boiling point. Separately collected, the amount of heat generated by tar combustion in the hot air generation furnace is reduced.

  At this time, the correlation between the carbide temperature and the hot air temperature (for example, a correlation map or a correlation coefficient) is obtained in advance by performing a combustion test or the like, and the hot air temperature when the carbide temperature indicates the upper limit temperature is determined by the correlation. Obtained from the map, correlation coefficient, etc., and set and registered as the upper limit temperature of the hot air temperature.If the hot air temperature is higher than the upper limit temperature, it is determined that the carbide temperature is also higher than the upper limit temperature, and the outside air supply fan is operated. It is advisable to adjust so that the amount of tar combustion is reduced. When the hot air temperature is higher than the upper limit temperature but the carbide temperature is not sufficiently raised as in the initial operation, the outside air supply fan is not operated manually or automatically. It is preferable to control it.

  Further, it is preferable to include a combustion air supply duct for guiding the outside air supplied from the outside air supply fan to the air-cooled heat exchanger into the hot air generating furnace.

  Furthermore, an outside air inlet is provided on the downstream side of the air-cooling heat exchanger of the combustion air supply duct so as to be openable and closable, and the residual oxygen concentration in the hot air downstream of the hot air generating furnace is a lower limit residual oxygen concentration set in advance. If it is lower than the above, it is preferable to open the outside air introduction port and introduce the outside air into the hot air generating furnace.

  Furthermore, in the middle of an exhaust duct that exhausts hot air supplied as an indirect heating source to the carbonization furnace, a drying furnace for drying woody biomass before carbonization or a sand that is a material of an asphalt mixture is dried. It is also possible to interpose a sand dryer to effectively utilize the heat quantity of the hot air generated by the combustion decomposition of the tar component in the hot air generating furnace without waste.

  Then, in the carbonization treatment apparatus for woody biomass having the above-mentioned structure, when carbonizing a carbide suitable for a charcoal fuel for a burner from a woody biomass such as a difficult-to-use material, some tar component remains in the carbide. The temperature range is, for example, about 400 to 500 ° C., the hot air temperature at that time is, for example, 1000 ° C., and the woody biomass is supplied in a predetermined amount into the carbonization furnace while indirectly heating under a reducing atmosphere. It is carbonized and recovered as a carbide having a desired property with a tar component remaining to some extent. On the other hand, the wood gas containing a flammable tar component generated by this carbonization treatment is supplied to the hot air generating furnace through the air-cooling heat exchanger and is combusted and decomposed by self-combustion. Hot air is supplied to the carbonization furnace as an indirect heating source.

  At this time, the amount of outside air supplied to the air-cooling heat exchanger is adjusted and controlled by the outside air supply fan so that the temperature of the carbide inside the carbonizing furnace or the temperature of the hot air downstream of the hot air generating furnace is maintained at a predetermined temperature. Alternatively, if the hot air temperature becomes higher than the predetermined temperature, the amount of outside air supplied by the outside air supply fan is increased to increase the amount of tar component separated and recovered from the wood gas, and the amount of tar combustion in the hot air generation furnace is reduced to reduce the amount of tar inside the furnace. Adjust the heat quantity at.

  Further, when the outside air supplied from the outside air supply fan to the air-cooling heat exchanger is supplied to the hot air generating furnace as combustion air for self-combustion through the combustion air supply duct, the temperature of the carbide and the temperature of the hot air are predetermined. While the temperature is below the temperature, the outside air is not supplied from the outside air supply fan, which may cause oxygen shortage in the hot air generating furnace. In that case, if the residual oxygen concentration detected by the oxygen concentration sensor provided downstream of the hot air generator falls below the preset lower limit residual oxygen concentration, open the outside air inlet provided in the middle of the combustion air supply duct. Introduce outside air into the hot air generator to avoid problems such as incomplete combustion and misfire.

  Thus, according to the carbonization apparatus for woody biomass, the air-cooled heat exchanger adjusts the amount of heat in the hot air generating furnace by separating and recovering the tar component, and further for combustion using the outside air for air cooling. It plays a role of supplying air and adjusting the temperature of the hot air generating furnace, and by this, the hot air temperature can be controlled and a carbide having a desired property can be produced.

  An embodiment of the present invention will be described below with reference to the drawings.

  Reference numeral 1 in the figure denotes a carbonization device for woody biomass, such as a carbonization furnace 2 for indirectly heating and carbonizing woody biomass such as pruned branches, rooting materials and bark, which are also called difficult-to-use materials, in a reducing atmosphere. , A hot air generating furnace 3 for generating hot air by burning and decomposing wood gas containing a combustible tar component generated by the carbonization in the carbonizing furnace 2 by self-combustion, and these carbonizing furnace 2 and hot air The generation furnace 3 is connected by a wood gas derivation duct 4 and a hot air supply duct 5, and the wood gas generated in the carbonization furnace 2 is supplied to the hot air generation furnace 3 through the wood gas derivation duct 4 while the hot air generation is generated. The hot air generated in the furnace 3 is supplied to the carbonization furnace 2 via the hot air supply duct 5 as an indirect heating source. Further, an exhaust duct 6 for exhausting the hot air supplied as an indirect heating source is connected to the carbonization furnace 2, and a drying process in which woody biomass is dried in advance before carbonization in the middle of the exhaust duct 6. A furnace 7 is interposed, and a downstream side thereof is provided with a bag filter 8 for capturing dust in exhaust gas, a main damper 9 for adjusting the amount of exhaust air, an exhaust fan 10, and a chimney 11.

  The carbonization furnace 2 rotatably supports an inner cylinder 13 formed by surrounding a plurality of scraping blades 12 on the inner wall surface of a cylindrical steel plate, and one end of the inner cylinder 13 is divided by a partition wall 14 to form a wood-based biomass. The supply hopper 15 for supply and the screw conveyor 16 are provided, while the other end is provided with a discharge hopper 17 that discharges a carbonized product generated by carbonizing woody biomass.

  An opening / closing damper 19 is vertically provided in two stages in the middle of the discharge chute 18 below the discharge hopper 17, and a screw conveyor 20 for discharging carbide is connected to a lower end portion of the discharge chute 18 to form a discharge hopper. When discharging the carbide discharged into the inside 17, the opening and closing dampers 19 are sequentially opened and closed so that one of the upper and lower opening and closing dampers 19 is always closed, and the inside of the screw conveyor 20 is discharged. Is always filled with the carbide being discharged, the outside air (oxygen) from entering into the inner cylinder 13 from the discharge port 21 at the end of the conveyor is blocked as much as possible, and the inside of the inner cylinder 13 is suitable for carbonization treatment. It is designed so that it can be maintained in a reducing atmosphere.

  Further, a water injection nozzle 22 is provided in the middle of the screw conveyor 20, and cooling water in a water storage tank 23 installed in the vicinity is supplied to the water injection nozzle 22 via a water supply pipe 24, so that the inside of the screw conveyor 20 is supplied. A predetermined amount of cooling water is sprayed onto the high temperature carbide flowing down to appropriately moisten and cool it to prevent problems such as scattering of the discharged carbide and spontaneous ignition.

  Reference numeral 25 in the figure denotes an outer cylinder through which hot air indirectly heating the wood-based biomass supplied into the inner cylinder 13 passes, and the outer circumference of the middle portion of the inner cylinder 13 in the longitudinal direction is maintained at an appropriate interval. The outer cylinder 25 is formed so as to surround the inner cylinder 13 with a hot air introduction port 26 at one end and a hot air discharge port 27 at the other end. After the woody biomass in the inner cylinder 13 is indirectly heated while flowing down along the outer periphery of the inner cylinder 13 in the flow direction and the co-flow direction of the woody biomass, the hot air discharge port 27 at the other end is discharged. I am trying to do it. In addition, a caster 28 for keeping heat is provided around the inner peripheral wall of the outer cylinder 25 so that the heat quantity of the hot air is effectively utilized for heating the woody biomass in the inner cylinder 13.

  On the other hand, the hot-air generating furnace 3 has a substantially L-shaped furnace body 29 in which the wood gas containing the combustible tar component discharged from the carbonization furnace 2 is introduced through the wood gas discharge duct 4 to be combusted and decomposed. The furnace main body 29 has a furnace length that takes about 2 seconds or more for the introduced wood gas to pass through, and the combustible tar component contained in the wood gas generated by the carbonization treatment of woody biomass. In addition, while the scattering unburned components such as fine carbides are completely combusted and decomposed by self-combustion while passing through the inside of the furnace main body 29 maintained in a high temperature atmosphere, the hot air generated at that time is The hot air supply duct 5 is used to supply the carbonization furnace 2 as an indirect heating source. Reference numeral 30 in the drawing denotes an auxiliary burner for supplying hot air into the furnace body 29 by using fossil fuel such as heavy oil or propane gas. The inside is preheated to the desired temperature and extinguished after the preheating is completed.

  Further, in the middle of the wood gas outlet duct 4 connecting the inner cylinder 13 of the carbonization furnace 2 and the hot air generating furnace 3, heat exchange is performed between the wood gas discharged from the inner cylinder 13 of the carbonization furnace 2 and the outside air, An air-cooling heat exchanger 31, which is capable of separating and recovering by condensing a part of the high-boiling-point tar component contained in the wood gas, is interposed.

  In the air-cooling heat exchanger 31, a plurality of steel pipes 33 having a predetermined diameter are piped in a vertically long casing 32 whose inside is divided into three chambers of upper, middle and lower layers so that the longitudinal direction thereof is substantially parallel to the vertical direction, The upper end opening of the steel pipe 33 is opened in the upper chamber 34a, while the lower end opening of the steel pipe 33 is opened in the lower chamber 34c, and the wood gas is introduced from the wood gas outlet duct 4 into the upper chamber 34a. Is designed to flow down in the steel pipe 33 and be led out into the lower chamber 34c.

  Further, reference numeral 35 in the figure is an outside air supply fan, and it is preferable that it is provided with an inverter so that the amount of blown air can be varied. The outside air supplied from the outside air supply fan 35 is introduced into the middle-layer chamber 34b, and cools the high temperature wood gas flowing down in the steel pipe 33 while passing around the middle portion of the steel pipe 33 to cool the high boiling point tar component. Is condensed and separated from the wood gas, dropped into a recovery tank 36 provided at the bottom of the lower layer chamber 34c, and recovered through a discharge pipe 38 having an on-off valve 37 in a drum can 39 or the like provided below. On the other hand, the wood gas from which a part of the tar component is separated is sent out from the wood gas outlet duct 4 on the downstream side to the hot air generating furnace 3. Further, the outside air supplied from the outside air supply fan 35 into the middle-layer chamber 34b and heated by heat exchange with the wood gas is heated by the hot air through the combustion air supply duct 40 whose base end is connected to the middle-layer chamber 34b. The combustion air for self-combustion is supplied to the generation furnace 3.

  Further, an outside air introduction port 41 is provided in the middle of the combustion air supply duct 40, and the opening degree of the outside air introduction port 41 is adjustable by an opening / closing damper 42. When the opening / closing damper 42 is opened. In addition, an appropriate amount of outside air is introduced from the outside air introduction port 41 into the furnace body 29 of the hot air generating furnace 3 through the combustion air supply duct 40.

  Further, inside the inner cylinder 13 of the carbonization furnace 2, a carbide temperature sensor 43 such as a thermocouple for detecting the temperature of the carbide in the furnace is provided. The carbide temperature sensor 43 may be a single unit or a plurality of units, but it is preferable to provide the carbide temperature sensor 43 at least in the vicinity of the end of the inner cylinder 13 where the carbonization process of the carbide is completed. Further, a transmitter 44, which captures signal data of the carbide temperature detected by the carbide temperature sensor 43 and wirelessly transmits the signal data, is fixed to the outer peripheral surface of the inner cylinder 13 which is a rotating body, while being separated from the inner cylinder 13. A receiver 45 that receives the signal data transmitted from the transmitter 44 in a non-contact manner is installed on the ground surface and the like, and the signal data of the carbide temperature received by the receiver 45 will be described later. A wireless telemeter device 46 configured to sequentially output the combustion amount controller is provided. As the carbide temperature sensor 43 provided in the inner cylinder 13, a radiation thermometer or the like that can detect the carbide temperature in a non-contact manner can be adopted instead of the thermocouple, but the inner cylinder 13 is filled with the carbonization process. Considering the possibility of measurement error due to the influence of dust and the like, it is more preferable to directly measure the carbide temperature with a thermocouple or the like as in this embodiment.

  Further, in the middle of the hot air supply duct 5 on the downstream side of the hot air generating furnace 3, a hot air temperature sensor 47 for detecting the hot air temperature derived from the hot air generating furnace 3 and an oxygen concentration sensor for detecting the residual oxygen concentration in the hot air. And 48.

  Reference numeral 49 in the figure denotes a tar combustion amount controller that controls and adjusts so as to reduce the tar combustion amount in the hot air generation furnace 3 by separating and recovering the tar component corresponding to the surplus heat amount from the wood gas discharged from the carbonization furnace 2. Then, the respective detection data such as the carbide temperature detected by the carbide temperature sensor 43, the hot air temperature detected by the hot air temperature sensor 47, the residual oxygen concentration detected by the oxygen concentration sensor 48, and the like are fetched, Also, the input / output unit 50 that outputs operation / control signals to various devices, the setting storage unit 51 that stores and stores various setting values that are preset and registered, and the respective detection data and the setting values are compared and calculated. The control unit 52 executes various controls based on the calculation result.

  In the setting storage unit 51, for example, with respect to a treatment temperature range suitable for carbonizing a carbide having a desired property, for example, the upper limit carbide temperature that is the upper limit thereof, or the wood gas derived from the carbonization furnace 2 is self-combusted. The lower limit residual oxygen concentration, which is the residual oxygen concentration remaining in the exhaust gas when completely combusted at the required minimum oxygen concentration, is preset and registered. On the other hand, when the control unit 52 determines that the carbide temperature detected by the carbide temperature sensor 43 is higher than the upper limit carbide temperature preset and registered in the setting storage unit 51, the outside air of the air-cooling heat exchanger 31 is determined. The supply fan 35 is operated to supply the outside air into the middle-layer chamber 34b of the casing 32, and the tar component corresponding to the surplus heat amount is separated and recovered from the wood gas flowing down in the steel pipe 33, and the tar combustion amount in the hot air generating furnace 3 is obtained. The adjustment is controlled so as to reduce.

  In order to adjust the temperature of the hot air from the hot air generator 3 on the upstream side, which is an indirect heating source, based on the temperature of the carbide in the inner cylinder 13 of the carbonization furnace 2, the air cooling heat exchanger 31 located further on the upstream side is used. When the amount of tar in wood gas is adjusted, control delay is likely to occur, so it is better to adjust the amount of tar in wood gas based on the hot air temperature, which is an indirect heating source, instead of the carbide temperature. This is more preferable because the control delay can be suppressed.

  At this time, the correlation between the carbide temperature and the hot air temperature which is an indirect heating source is obtained in advance by performing a combustion test or the like, and the hot air temperature when the carbide temperature shows the upper limit temperature is set as the upper limit hot air temperature. If the hot air temperature detected by the hot air temperature sensor 47 is higher than the upper limit hot air temperature, it is determined that the carbide temperature is also higher than the upper limit temperature, and the outside air supply fan 35 is operated to operate the air cooling heat. It is advisable to supply the outside air to the exchanger 31 to separate and recover the tar component corresponding to the surplus heat amount in the wood gas, and to perform the control so as to reduce the tar combustion amount in the hot air generating furnace 3.

  Even in the above case, the carbide temperature detected by the carbide temperature sensor 43 may be taken in together and monitored as a reference value or the like, and only the hot air temperature is the upper limit temperature, for example, at the beginning of operation. The outside air supply fan 35 is operated only when the temperature of the carbide is not sufficiently high, and if the tar combustion amount is reduced as it is, there is a possibility that the carbonized inadequately carbonized will be discharged. It is more preferable to control manually or automatically so as not to turn it off.

  Further, a combustion air supply fan or the like for supplying combustion air for self-combustion may be separately provided to the hot air generating furnace 3 so that the outside air supplied from the outside air supply fan 35 to the air-cooling heat exchanger 31 is released to the atmosphere. It is good, however, as in the present embodiment, the outside air heated by heat exchange with wood gas is supplied to the hot air generating furnace 3 through the combustion air supply duct 40 and used as combustion air for self-combustion. If so, it becomes possible to effectively increase the combustion efficiency.

  However, in this case, for example, if the carbide temperature or the hot air temperature does not reach the preset upper limit carbide temperature or the upper limit hot air temperature, the tar combustion amount controller 49 determines that there is no excess heat amount, and the outside air supply fan 35 Therefore, the hot air generating furnace 3 is not supplied with the combustion air and the oxygen concentration is insufficient, so that the operating conditions of the outside air supply fan 35 are uniform. Even when outside air is supplied, this outside air heats up due to heat exchange with high-temperature wood gas, causing thermal expansion, and the amount of oxygen per unit amount of air (oxygen concentration) decreases, resulting in insufficient oxygen concentration. May occur, and incomplete combustion or misfire may occur in some cases, but the tar combustion amount controller 49 sequentially takes in the residual oxygen concentration in the hot air detected by the oxygen concentration sensor 48, and Is lower than the lower limit residual oxygen concentration set in advance, it is determined that the oxygen concentration is insufficient, the opening / closing damper 42 of the outside air inlet 41 is opened regardless of the hot air temperature or the carbide temperature, and the outside air at room temperature is heated by the hot air generating furnace 3 I am trying to introduce it inside.

  In addition, while branching the middle of the wood gas derivation duct 4 and connecting one side to the air cooling heat exchanger 31, the other side is not passed through the air cooling heat exchanger 31 but is used as a bypass duct 53 as a downstream side wood gas derivation duct 4 The switching dampers 54, 55 may be openably and closably provided in the middle of each duct. For example, when the hot air temperature does not reach the upper limit hot air temperature, or when the hot air temperature adheres to the inside of the steel pipe 33 of the air-cooling heat exchanger 31. When performing maintenance such as removal of the tar component, the switching dampers 54 and 55 are controlled to open and close so that the wood gas flows down to the bypass duct 53 side.

  Further, the hot air supplied as an indirect heating source into the outer cylinder 25 of the carbonization furnace 2 still has a considerable amount of heat at the time of being discharged from the hot air discharge port 27, and this exhaust gas is exhausted from the exhaust duct 6 to the exhaust duct 6. By supplying the woody biomass before carbonization, which is interposed on the way, into the drying furnace 7 for drying, the heat quantity of the exhaust gas can be effectively utilized without waste. The drying furnace 7 has a very general rotary kiln structure, and rotatably supports a cylindrical kiln body 56 having a plurality of scraping blades (not shown) around its inner peripheral surface so as to be rotatable. The kiln body 56 is provided with a wood-based biomass charging chute 57 at one end and a discharge hopper 58 at the other end, so that the wood-based biomass charged from the charging chute 57 into the kiln body 56 is discharged from the exhaust duct 6. The drying process is performed while contacting the supplied exhaust gas so that the carbonization process in the carbonization furnace 2 in the next step can be performed more efficiently.

  It should be noted that instead of the drying furnace 7, a heat dryer having a similar structure, for example, a sand dryer for drying the sand, which is a raw material of the asphalt mixture, may be used to effectively use the heat quantity of the exhaust gas.

  When carbonizing a carbonaceous material suitable for a charcoal fuel for a burner from a woody biomass such as a difficult-to-use material using the carbonaceous woody biomass carbonization apparatus 1 having the above-described structure, first, to some extent Treatment temperature range (for example, about 400 to 500 ° C.) in which the tar component remains is determined in advance by a combustion test or the like, and its upper limit value (for example, 500 ° C.) is set as the upper limit carbide temperature, and hot air temperature at that time (for example, 1000 ° C. ) Is set as the upper limit hot air temperature, and the lower limit residual oxygen concentration is set and registered in the setting storage unit 51 of the tar combustion amount controller 49.

  Then, after the auxiliary burner 30 of the hot air generating furnace 3 is ignited and preheated, wood-based biomass is supplied into the inner cylinder 13 of the carbonization furnace 2 by a predetermined amount at a sufficient amount from the carbonization furnace 2. When the wood gas starts to be generated (when the hot air generating furnace 3 is in a state capable of self-combustion), the auxiliary burner 30 is extinguished. The wood-based biomass supplied into the inner cylinder 13 of the carbonization furnace 2 flows down while being scooped up by a plurality of scooping blades 12 provided in the furnace, during which the outer cylinder 25 from the hot air generating furnace 3 flows. It is heated to the above temperature indirectly and in a reducing atmosphere by the hot air supplied therein, and is gradually discharged from the discharge hopper 17 as a carbide in a state in which the tar component remains to some extent. The carbide discharged to the discharge hopper 17 is appropriately moistened and cooled by the cooling water sprayed from the water spray nozzle 22 while being sequentially sent out by the screw conveyor 20, so that there is no fear of scattering or spontaneous combustion. Recovered after processing.

  On the other hand, the wood gas containing a combustible tar component generated by this carbonization treatment is supplied to the hot air generating furnace 3 through the wood gas outlet duct 4 and is combusted and decomposed by self-combustion. The high-temperature hot air is supplied to the carbonization furnace 2 as an indirect heating source.

  At this time, the tar combustion amount controller 49 sequentially takes in the hot air temperature detected by the hot air temperature sensor 47 (S1) as shown in the flowchart of FIG. 2, and presets it in the hot air temperature and the setting storage unit 51. The registered upper limit hot air temperature is compared (S2), and if it is determined that the hot air temperature is higher than the upper limit hot air temperature, the outside air supply fan 35 is operated to supply the outside air to the air-cooled heat exchanger 31. Then, (S3), the tar component of the surplus heat amount is separated and recovered from the wood gas to reduce the tar combustion amount in the hot air generating furnace 3, while the outside air supply fan 35 is stopped if the hot air temperature does not reach the upper limit hot air temperature. Then, the supply of outside air to the air-cooling heat exchanger 31 is stopped (S4).

  Next, the residual oxygen concentration in the hot air detected by the oxygen concentration sensor 48 downstream of the hot air generating furnace 3 is fetched (S5), and the residual oxygen concentration and the lower limit residual oxygen concentration preset in the setting storage unit 51 are registered. (S6), and if it is determined that the residual oxygen concentration is higher than the lower limit residual oxygen concentration, the open / close damper 42 of the outside air inlet 41 is closed (S7) while the remaining oxygen concentration is the lower limit residual oxygen concentration. If the concentration is lower than the concentration, the opening / closing damper 42 of the outside air inlet 41 is opened (S8), and the outside air at room temperature is introduced into the hot air generating furnace 3 to prevent problems such as incomplete combustion and misfire. Then, it is determined whether or not the operation is to be ended (S9), and when the operation is to be ended, the process proceeds to END, while when the operation is to be continued, the process is returned to S1 again.

  In the above embodiment, the upper limit hot air temperature is set, and if the hot air temperature becomes higher than the upper limit temperature, the outside air supply fan 35 is operated to supply the outside air to the air-cooling heat exchanger 31, but the outside air supply fan It is preferable that the amount of air blown by 35 be variable and the amount of outside air supplied by the outside air supply fan 35 be adjusted so as to maintain the temperature of the carbide in the carbonization furnace 2 or the temperature of the hot air downstream of the hot air generation furnace 3 at a predetermined temperature. Further, if the residual oxygen concentration is below the lower limit residual oxygen concentration, it is preferable to take in the outside air while finely adjusting the opening degree of the opening / closing damper 42 of the outside air inlet 41.

  Due to variations in the properties (moisture content, etc.) of the woody biomass to be carbonized, the hot air temperature detected by the hot air temperature sensor 47 becomes too low, and even if the supply of outside air is stopped, it will fall within the appropriate processing temperature range. If not, for example, the supply speed of the screw conveyor 16 for supplying the woody biomass is reduced to temporarily reduce the amount of the material to be carbonized in the inner cylinder 13, or the auxiliary combustion of the hot air generating furnace 3 is performed. The burner 30 may be re-ignited to supply hot air temporarily.

  Thus, in the carbonization treatment apparatus 1 for woody biomass of the present invention, as shown in FIG. 3, for example, woody biomass such as difficult-to-use materials discharged from forests, parks, etc. and produced from a quarry. By accepting sand with a high water content and carbonizing the woody biomass, it can be recovered as charcoal fuel useful for burners, tar as an asphalt extender, and while utilizing the exhaust heat during carbonization. Sand with high water content can be dried and collected as easy-to-use dry sand. Then, the recovered charcoal fuel, tar, and dry sand can be effectively used as a part of a material or a fuel for producing an asphalt mixture by supplying it to, for example, an asphalt mixture manufacturing plant. It will be possible to establish the use of difficult-to-use materials such as pruned branches, root cuttings, and bark, which had been abandoned without any use, and it will greatly contribute to the activation of forestry. On the other hand, even in the asphalt mixture manufacturing industry, it is possible to substitute some of the materials and fuels for cost reduction, and because the fuel is derived from wood biomass, CO2 reduction based on carbon neutral can be expected. Is suitable.

  INDUSTRIAL APPLICABILITY The present invention can be widely used as a carbonization treatment device for various woody biomass, including difficult-to-use materials such as pruned branches, rooting materials, and bark.

1 ... Carbonization apparatus for woody biomass 2 ... Carbonization furnace 3 ... Hot air generating furnace 4 ... Wood gas outlet duct 5 ... Hot air supply duct 6 ... Exhaust duct 7 ... Drying furnace (sand dryer)
13 ... Inner cylinder 25 ... Outer cylinder 31 ... Air-cooled heat exchanger 33 ... Steel pipe 35 ... Outside air supply fan 36 ... Recovery tank 40 ... Combustion air supply duct 41 ... Outside air inlet 42 ... Open / close damper 43 ... Carbide temperature sensor 47 ... Hot air Temperature sensor 48 ... Oxygen concentration sensor 49 ... Tar combustion amount controller

Claims (4)

A carbonization furnace that indirectly heats woody biomass in a reducing atmosphere to carbonize it, and a hot air generation that combusts and decomposes wood gas generated by the carbonization of woody biomass in the carbonization furnace by self-combustion to generate hot air A carbonization treatment device for woody biomass, which is provided with a furnace and supplies hot air generated in the hot air generation furnace to the carbonization furnace as a heat source for indirect heating, the carbonization furnace and the hot air generation furnace Heat exchange between the wood gas discharged from the carbonization furnace and the outside air supplied from the outside air supply fan to condense a part of the high boiling point tar component contained in the wood gas, enabling separation and recovery. Along with an air-cooled heat exchanger, a carbide temperature sensor for detecting a carbide temperature in the furnace in the carbonization furnace, or a hot air temperature sensor for detecting a hot air temperature derived from the hot air generation furnace downstream of the hot air generation furnace is provided. , Serial supplied from the outside air supply fan as carbides temperature or hot air temperature of the hot air generating furnace downstream detected by the hot air temperature sensor in said carbonizing furnace detected by the carbides temperature sensor is maintained at a predetermined temperature outside air A carbonization treatment device for woody biomass, comprising a tar combustion amount controller for adjusting and controlling the amount of tar combustion in the hot air generating furnace .   The woody biomass carbonization apparatus according to claim 1, further comprising a combustion air supply duct for guiding the outside air supplied from the outside air supply fan to the air-cooling heat exchanger into the hot air generating furnace. -Based biomass carbonization equipment.   The woody biomass carbonization apparatus according to claim 2, wherein an outside air inlet is openably provided on a downstream side of the air-cooling heat exchanger of the combustion air supply duct so as to open and close the hot air downstream of the hot air generating furnace. If the residual oxygen concentration is lower than a preset lower limit residual oxygen concentration, the outside air introduction port is opened so that the outside air is introduced into the hot air generating furnace.   The carbonization apparatus for woody biomass according to any one of claims 1 to 3, wherein the woody biomass before carbonization is dried in the middle of an exhaust duct that exhausts hot air supplied to the carbonization furnace as a heat source for indirect heating. A carbonization treatment device for woody biomass, characterized in that a drying oven for treatment or a sand dryer for drying treatment of sand which is a material of an asphalt mixture is interposed.

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